Method of automatic standardized calibration for infrared sensing device

ABSTRACT

A method for calibrating automatic infrared sensing devices having control modules, an IR detector, and an IR emitter by using a select infrared emitter/detector pair to calibrate a plurality of control modules wherein an appropriate infrared emitter input value to the select infrared emitter is obtained to provide a given output from the select infrared detector in response to infrared radiation reflected from a known test object, and the appropriate infrared emitter input value is then determined and stored permanently in one or more control modules as a calibration standard.

This application claims the benefit of an earlier filed provisionalpatent application titled “REMOTELY MANAGED AUTOMATIC DISPENSINGAPPARATUS AND METHOD,” application Ser. No. 60/242,898, filed Oct. 24,2000, the disclosure of which is hereby incorporated by reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates generally to the field of infrareddetecting devices and more particularly to the automatic standardizedcalibration of infrared detection devices.

2. Technical Background

Various methods have been employed to electronically control water flowthrough a water control device such as a faucet or spigot. Among theaccepted and conventional methods is the use of an optical sensor fordetecting reflections from an infrared (“IR”) source or IR emitter. Whenprocessing electronics determine the reflection has exceeded a thresholdvalue, a control signal opens a solenoid valve. Generally speaking, apulsed IR beam is reflected from an object (such as a user's hands) andsensed to determine whether to activate or deactivate a solenoid valveto control water flow from the water control device. Pulsed IR sensingremains at the forefront of sensing techniques used with these types ofdevices due in part to its reasonable performance and low cost.

Because of variations in processing circuits, emitter characteristicsand sensor characteristics, it is necessary to calibrate the IR system.Calibration of infrared sensing devices such as, for example,automatically activated flow control devices is labor intensive andinefficient with respect to devices presently on the market. The lostcost IR sensing devices employed in automatically activated flow controldevices vary with respect to power requirements, performance, and othercriteria. As a result, readings taken by these IR sensing units (such aswhether a user's hands are present beneath the aerator of a faucet) aregenerally non-uniform from device to device, and therefore often resultin improper activation and deactivation of some devices. Similarly, asbattery power for these devices decreases over time, so does the poweroutput of the IR sensing devices. Moreover, water droplets sprayed orotherwise deposited on or near the IR detector lens or lens cover havebeen known to cause such devices to malfunction. As a result, manualcalibration of conventional infrared sensing systems of automaticallyactivated flow control devices is generally required during initialinstallation, and thereafter on a frequent basis following extendedperiods of use.

Most infrared sensing units have an IR emitter and IR detector embeddedin an electronics board in the collar of a faucet. During manufacturing,each emitter and detector has to be screened, requiring technicians tomanually adjust settings when they go through calibration steps. Atechnician is required to make measurements and adjustments to the mainelectronics board which is time consuming and costly.

SUMMARY OF INVENTION

The present invention provides a method for calibrating infrareddetecting devices which detect the presence of an object by detecting anIR reflection. The output of the IR detector is calibrated by a controlmodule which receives the output of the IR detector and regulates theoutput of the IR emitter. A single standard pair of an IR detector andan IR emitter is sufficient to calibrate an unlimited number of controlmodules. The method eliminates the need to manually calibrate and adjusteach IR detector and IR emitter that is part of the infrared detectingdevice. The method uses a standard IR detector and IR emitter withoutput characteristics in the middle of a suitable operating range. Thecontrol module activates the IR emitter with an input value to emit IRradiation which is reflected from a standard object at a standarddistance from the IR emitter to an IR detector which is also a standarddistance from the object. The output from the IR detector is transmittedto a control module. If the IR detector output is out of the desiredrange, a calibration manager directs the signal processor to increase ordecrease the output of the IR emitter. This process is repeated untilthe output of the IR detector is within midrange. The value of thecorresponding input to the IR emitter to achieve this midrange outputvalue of the IR detector is stored in the nonvolatile memory of thecontrol module and the calibration manager reprograms itself to use thiscalibration value of input to the IR emitter as a reference standard.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary embodiment of a fluid dispensing system inaccordance with the present invention.

FIG. 2 is a block diagram illustrating the fluid dispensing systemdepicted in FIG. 1.

FIG. 3 is a flow chart illustrating the architecture and functionalityof an infrared detection system depicted in FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the following description details the preferred embodiments of thepresent invention, it is to be understood that the invention is notlimited in its application to the details of construction andarrangement of the parts illustrated in the accompanying drawings, sincethe invention is capable of other embodiments and of being practiced invarious ways.

FIGS. 1 and 2 show a fluid dispensing system that employs an infrareddetection system 9 in accordance with the present invention. As shown inFIG. 1, the fluid dispensing system 8 includes an automated faucet 10.Automated faucet 10 has plumbing 11 in line with a solenoid valve 12 anda mixing valve 13, which is connected to a hot water source 14 and acold water source 15. Faucet 10 also has IR emitter 16 and IR detector17 on a sensor board in a collar 18 around faucet 10. The sensor boardis preferably connected electrically to control module 19 by connector20. The connector 20 provides IR emitter 16 and IR detector 17 interfaceto module 19. Control module 19 output is also connected electrically tosolenoid 12 by connector 21.

In the example shown by FIG. 1 the calibration manager 38 (see FIG. 2)in control module 19 controls the intensity and duration of each pulseemitted from IR emitter 16. When a user places his or her hands nearfaucet 10, the emitted IR radiation is reflected from the hands to IRdetector 17. IR detector 17 sends an output to calibration manager 38which may then signal solenoid controller 40 (see FIG. 2) to opensolenoid valve 12 so that water will flow out of faucet 10. When theuser removes his or her hands from faucet 10, the absence ofsufficiently detected IR radiation signals control module 19 to close ordeactivate solenoid 12.

To insure proper operation it is desirable to calibrate the IR emitter16, IR detector 17, associated circuitry amplifiers 30 and 31, andsignal processor 34. This may be performed during manufacturing andheretofore has required manual calibration. In accordance with thepresent invention, calibration can now be performed automatically by thecalibration manager 38 using electronic or software methodology or acombination thereof.

FIG. 2 shows the components of an infrared detecting device used in thecalibration procedure for the present invention. Sensor board 22 incollar 18 has IR emitter 16 and IR detector 17 which are connected to IRemitter amp 30 and IR detector amp 31, respectively. Control module 19has a power supply 33 which provides power to a signal processor 34, aprogrammable memory 35 with computing capability, a solenoid powersource 36, and a solenoid switch 37. Memory 35 also has a calibrationmanager 38, calibration data 39, and solenoid controller 40. Thesolenoid switch 37 under the control of solenoid controller 40, can opensolenoid valve 12. There are at least two programs in memory 35, one insolenoid controller 40 for turning the faucet 10 on and off, and theother in calibration manager 38 for calibrating the outputs of IRemitter 16 and IR detector 17 during manufacture and during commercialuse. If desired, control module 19 may communicate with a remotecomputer 39 so that computer 39 can remotely monitor the memory 35 forcomputing capability and calibration values obtained during acalibration procedure. Computer 39 typically is adapted to use any ofthe known operating systems and comprises a processor, random accessmemory, read only memory, disk drives, display, communicationsapplications, and the like. The value of outputs produced by the IRdetector and IR emitter will have optimal or standard ranges in whichthe infrared detecting device can operate satisfactorily. Thesepredetermined maximum and minimum output ranges and the midpoint ofthese output ranges can be entered into calibration data 39 in memory35. The infrared detection and calibration system 9 includes sensorboard 22, memory 35, and signal processor 34.

Calibration manager 38 is configured to direct signal processor 34 tosend an appropriate input signal to IR emitter amp 30 to cause IRemitter 16 to emit a given amount of infrared radiation. This radiationis detected by IR detector 17 and an input signal is thereby sent to IRdetector amp 31 which then sends an amplified output signal to signalprocessor 34. Signal processor 34 then transmits this output signal tocalibration manager 38. Calibration manager 38 is further configured toevaluate this output signal based on a standard range of valuescontained in calibration data 39 and thereby execute appropriatecommands to signal processor 34 regarding input signals to IR emitter 16to emit infrared radiation, or to solenoid controller 40 to directsignal processor to open or close solenoid valve 12.

FIG. 3 shows a method of the present invention for calibrating the IRemitter 16 and IR detector 17 with connected circuitry in control module19 during manufacture or during commercial use. The present methodologyemployed in the IR detection system 9 requires the use of a selectedpair consisting of a single IR emitter and a single IR detector whichserves as a standard for calibrations of multiple control modules. Thisselected pair may be thought of as a golden standard. In the example ofthe automatic faucet, it may be considered a standard or “golden” collar18, as shown in FIG. 1. The standard collar is connected to a controlmodule 19 to conduct a calibration reflection test. Typically, in thistest, a white card is placed a given distance from the IR emitter 16,simulating the hands of a user, for example.

Prior to activation of IR emitter 16 by control module 19, IR detector16 will detect background IR radiation. In addition, when IR emitter 16is activated by control module 19, control module 19 provides an inputsignal to IR emitter 16 whereby IR emitter 16 produces an infraredsignal or pulse (IR radiation) having an amplitude based on this inputsignal. In the absence of the IR emitter energy, some IR radiation mayreflect back from other surrounding surfaces. This background andrandomly reflected IR radiation (sometimes referred to as “ambientinfrared radiation”) is detected, measured, and can be used to make acorrection for reflected IR radiation from the white card (or user'shands), by calibration manager 38 in memory 35 of control module 19(step 43). The reflection test is then initiated by calibration manager38 in memory 35 of control module 19. Calibration manager 38 directssignal processor 34 to activate IR emitter 16 to emit a known amount ofIR radiation, which is reflected from the white card to the IR detector17. IR detector 17 thereby sends an output signal to the signalprocessor 34, the strength or amplitude of the output signal beingproportional to the strength of the detected infrared radiation (step44).

The signal processor 34 sends the IR detector output signal to controlmanager 38 in memory 35 of control module 19 which determines whetherthe output signal is within the predetermied range or near theapproximate midpoint within the predetermined range of standard valuescontained in calibration data 39 (step 45). If not, control module 19,through signal processor 34, increases or decreases the output of the IRemitter by increasing or decreasing the output of IR emitter amp 30 adesired increment (step 46) by sending an appropriate input signal tosaid IR emitter amp 30 and, hence, to IR emitter 16. The reflection testis then repeated until the IR detector output is within thepredetermined range, preferably near the midrange (steps 44, 45, 46).Correction can be made to the detector output value, if desired, bysubtracting randomly reflected IR generated output from the detectoroutput generated by reflection from the white card.

If the IR detector output is within the predetermined range or at ornear the midrange, the value of the IR emitter input that generated thesatisfactory IR detector output is measured by said signal processor 34and is sent from said signal processor 34 to calibration data 39 wherethe input value is stored permanently in nonvolatile memory (step 47).Calibration manager 38 is configured to then reprogram itself andthereafter to generate an emitter input signal based on the stored valueuntil the next recalibration (step 48).

With the standardized calibration method of the present invention asingle golden collar comprising one emitter/detector pair can be used tocalibrate an unlimited number of control modules 19. The calibrationoccurs in the calibration manager 38 in memory 35 of control module 19,electronically or with software, or a combination thereof. This method,accordingly, facilitates the manufacture and maintenance of infrareddetection devices by avoiding the need to manually calibrate the IRdetector and/or the IR emitter that are manufactured with each controlmodule 19.

The foregoing description has been limited to specific embodiments ofthis invention. It will be apparent, however, that variations andmodifications may be made by those skilled in the art to the disclosedembodiments of the invention, with the attainment of some or all of itsadvantages and without departing from the spirit and scope of thepresent invention. For example, inputs to IR emitter 16 or outputs fromIR detector 17 may be measured in current or voltage. Various types ofIR emitters and/or detectors may be employed to implement the IR emitter16 and/or the IR detector 17 of the present invention. Sensor board 22may have other structural features contained therein, such as amicroprocessor or an IRDA photodiode for diagnostic and maintenancefunctions, or a power supply and power source. IR emitter amp 30 iscontained in control module 19, but could be contained in sensor board22. Control module 19 may have any suitable type of microprocessor orcomputer to perform programming, software implementation, and datastorage and memory. The control module may use an AC source of powerinstead of batteries. The white card may be replaced by any desiredobject for reflecting emitted infrared radiation.

It will be understood that various changes in the details, materials,and arrangements of the parts which have been described and illustratedabove in order to explain the nature of this invention may be made bythose skilled in the art without departing from the principle and scopeof the invention as recited in the following claims.

We claim:
 1. A method for calibrating an infrared sensing devices,comprising: a) storing a predetermined infrared detector output range ina control module; b) emitting and detecting infrared radiation with aselect infrared emitter/detector pair; c) comparing the output value ofsaid select infrared detector to said predetermined output range; and d)calibrating multiple control modules by determining and storing aninfrared emitter input value that produces an output value within saidpredetermined output range, using the same select infraredemitter/detector pair for the multiple control modules.
 2. The methodaccording to claim 1 further comprising said computer storing saidinfrared emitter input value in said control module memory.
 3. Themethod according to claim 2 further comprising said control modulesreprogramming itself to use said infrared emitter input value as acalibration standard for infrared detector output.
 4. The methodaccording to claim 3 wherein said control module has a signal processorto measure said output of said infrared detector, to increase ordecrease infrared radiation output of said infrared emitter, to measuresaid infrared emitter input value, and to send said emitter input valueto a software database in said control module.
 5. The method accordingto claim 3 wherein said output of said infrared detector is electriccurrent or electric voltage, or a combination thereof.
 6. The methodaccording to claim 3 wherein said control module increases or decreasesoutput of said infrared emitter by altering electric current or voltageor a combination thereof of an input signal to said infrared emitter. 7.The method according to claim 3 wherein said select infraredemitter/detector pair comprises photodiodes.
 8. The method according toclaim 3 wherein said select infrared emitter/detector pair is containedwithin a collar for calibration of an infrared automatic sensing flowsystem.
 9. A method for calibrating infrared sensing devices,comprising: a) measuring a first output of a single infrared detector inresponse to background and randomly reflected emitted infraredradiation; b) measuring a second output of said single infrared detectorin response to emitted infrared radiation from a single infrared emitterand reflected from a test object; c) subtracting said first output fromsaid second output and storing the resulting net output of said infrareddetector in one or more control modules; d) comparing said net output ofsaid infrared detector to a predetermined range of infrared detectoroutput values in one or more control modules; and e) increasing ordecreasing infrared emitter input value in one or more control modulesto provide an infrared emitter radiation output so that said net outputof said infrared detector is within said predetermined infrared detectoroutput range.
 10. The method according to claim 9 further comprisingstoring said infrared emitter input value in said control module memory.11. The method according to claim 10 further comprising said controlmodule reprogramming itself to use said infrared emitter input value asa calibration standard for infrared detector output.
 12. The methodaccording to claim 11 wherein said control module has a signal processorto measure said output of said infrared detector, to increase ordecrease infrared radiation output of said infrared emitter, to measuresaid infrared emitter input value, and to send said emitter input valueto a software database in said control module.
 13. A method according toclaim 11 wherein said output of said infrared detector is electriccurrent or electric voltage, or a combination thereof.
 14. A methodaccording to claim 11 wherein said control module increases or decreasesoutput of said infrared emitter by altering electric current or voltageor a combination thereof of an input signal to said infrared emitter.15. A method according to claim 11 wherein said infrared emitter andsaid infrared detector are photodiodes.
 16. A method according to claim11 wherein said infrared emitter and said infrared detector arecontained within a collar for calibration of an infrared automaticsensing flow system.
 17. A method according to claim 11 wherein saidinfrared emitter and said infrared detector can be used to calibrate aplurality of control modules.
 18. A system for calibrating infraredsensing devices, comprising: a) a single infrared emitter and a singleinfrared detector; b) one or more programable control modules withmemory and a calibration manager; c) said control module havingcalibration data including a standard predetermined infrared detectoroutput range of values; and d) said calibration manager configured toprovide an infrared emitter input value for said infrared emitter toproduce an infrared emitter radiation output so that output from saidinfrared detector receiving said infrared radiation reflected from anobject is within said predetermined infrared detector output range inone or more control modules.
 19. The system according to claim 18wherein said control module is configured to further store said infraredemitter input value in said control module memory.
 20. The systemaccording to claim 19 further comprising said control modulereprogramnming itself to use said infrared emitter input value as acalibration standard for infrared detector output.
 21. The systemaccording to claim 20 wherein said control module has a signal processorto measure said output of said infrared detector, to increase ordecrease infrared radiation output of said infrared emitter, to measuresaid infrared emitter input value, and to send said emitter input valueto calibration data in said control module.
 22. The system according toclaim 20 wherein said infrared emitter and said infrared detector arecontained within a collar for calibration of an infrared automaticsensing flow system.
 23. The system according to claim 20 wherein saidsingle infrared emitter and said single infrared detector are configuredto calibrate a plurality of control modules.
 24. The system according toclaim 20 wherein infrared detector output in response to background andrandomly reflected emitted infrared radiation is subtracted frominfrared detector output in response to emitted infrared radiationreflected from a test object to obtain a net infrared detector output.25. The system according to claim 24 wherein said control moduleprovides an infrared emitter input value to produce a net infrareddetector output equal to said predetermined infrared detector outputrange in said control module.
 26. The system according to claim 20wherein infrared detector output in response to background and randomlyreflected emitted infrared radiation is subtracted from infrareddetector output in response to emitted infrared radiation reflected froma test object to obtain a net infrared detector output.
 27. The systemaccording to claim 26 wherein said control module provides an infraredemitter input value to produce a net infrared detector output equal tosaid predetermined infrared detector output range in said controlmodule.